diff -Nru netkit-telnet-ssl-0.17.41+really0.17/debian/changelog netkit-telnet-ssl-0.17.41+really0.17/debian/changelog
--- netkit-telnet-ssl-0.17.41+really0.17/debian/changelog	2023-02-14 14:53:12.000000000 +0000
+++ netkit-telnet-ssl-0.17.41+really0.17/debian/changelog	2023-03-04 21:36:56.000000000 +0000
@@ -1,3 +1,12 @@
+netkit-telnet-ssl (0.17.41+really0.17-4) unstable; urgency=high
+
+  * QA upload.
+
+  [ Marcos Marado ]
+  * Fix ring buffer overflow. (Closes: #659415)
+
+ -- Bastian Germann <bage@debian.org>  Sat, 04 Mar 2023 22:36:56 +0100
+
 netkit-telnet-ssl (0.17.41+really0.17-3) unstable; urgency=medium
 
   * QA upload.
diff -Nru netkit-telnet-ssl-0.17.41+really0.17/debian/patches/710-ring-buffer-overflow.diff netkit-telnet-ssl-0.17.41+really0.17/debian/patches/710-ring-buffer-overflow.diff
--- netkit-telnet-ssl-0.17.41+really0.17/debian/patches/710-ring-buffer-overflow.diff	1970-01-01 00:00:00.000000000 +0000
+++ netkit-telnet-ssl-0.17.41+really0.17/debian/patches/710-ring-buffer-overflow.diff	2023-03-04 19:59:22.000000000 +0000
@@ -0,0 +1,20 @@
+Author: Mikolaj Izdebski <zurgunt@gmail.com>
+Description: Fixing a buffer overflow when top == bot
+Bug-Debian: https://bugs.debian.org/659415
+Last-Update: 2023-03-04
+
+--- netkit-telnet-0.17/telnet/ring.cc	2012-02-10 22:50:42.000000000 +0100
++++ ring.cc	2012-02-10 22:49:54.000000000 +0100
+@@ -138,11 +138,11 @@
+     while (count > 0) {
+ 	int bot = tail;
+ 	int top = head;
+ 	if (top < bot) top = size;
+ 	if (marked > bot) top = marked;
+-	assert(top-bot > 0 && top-bot <= count);
++	assert(top-bot >= 0 && top-bot <= count);
+ 
+ 	int n;
+ 	if (marked==bot) n = binding->writeurg(buf+bot, top-bot);
+ 	else n = binding->write(buf+bot, top-bot);
+ 	if (n < 0) { busy=0; return -2; }
diff -Nru netkit-telnet-ssl-0.17.41+really0.17/debian/patches/series netkit-telnet-ssl-0.17.41+really0.17/debian/patches/series
--- netkit-telnet-ssl-0.17.41+really0.17/debian/patches/series	2023-02-14 14:53:12.000000000 +0000
+++ netkit-telnet-ssl-0.17.41+really0.17/debian/patches/series	2023-03-04 19:59:44.000000000 +0000
@@ -61,3 +61,4 @@
 telnet-netwritebuf-fix.diff
 use-cmake-as-buildsystem.patch
 700-fix_UTF8.diff
+710-ring-buffer-overflow.diff